AG-AC90 Review - in the Dominican Republic

[Barry_Green]

I wonder if these guys make a note of shutter/iris settings when testing "sharpness" ?

Yes, that would be certainly informative to know.

As Chris has said, yes -- I consider external ND filtration mandatory with this camera when used in bright light conditions, because you cannot/should not/must not go stopping the iris down to f/11 or anywhere close to it.

If they tested an AC90 and found it "soft", that can only be attributed to not understanding the system and using it in error. I repeat, the AC90 is razor sharp, period.

 

[steve4505]

Hi Lou

I'm not sure if the 90 has the same system as the 40/80 but in full auto (or just auto iris) you are seldom at anything like F11. My 82's auto change the iris/ND combo AND the shutter so on a bright day my shutter will be up a 1/2000th which probably allows the iris to be lower. Barry mentions that the ND/shutter combo work up to F6.8 if I'm not mistaken so really the only time you might get a res drop would be in bright sunlight so there is certainly nothing wrong with popping on an ND if you are shooting in bright sun.

My tests are confirming your example. Its generally keeping max around f7.2 then bumping the shutter speeds. I was getting shutter speeds bumped to 1/500 and now I am blind because I did that test. :happy:

I think it was also Barry who suggested restricting the iris on the bigger sensor 130/160 to an absolute minimum of F8 (any smaller and you will lose res) and suggested sweet spot seemed to be F5.6 - Maybe they tested it in bright lighting in full manual and locked the shutter at 1/50th which closed the iris. The solution in bright light and full auto is a simple ND filter and Barry has already suggested this to AC-90 users. Put the big brother AC-160 into manual, turn the ND filters to OFF and see who the image degrades and that is with 1/3rd chips not 1/4.7 ones. I wonder if these guys make a note of shutter/iris settings when testing "sharpness" ?

Chris

I just got Barry's book on the 90 (its so incredibly helpful I just can't express how good it is), Barry is recommending not letting the iris to choke down below f8, so the above internal automatic settings would correspond with what the camera is attempting to do. Also he's saying from Open to f8 is sharp.

 

[Barry_Green]

I have no idea what he is saying.

It's intended to sound impressive while ignoring that fact that they're dead wrong about the results they got -- if they truly understood what they were saying, they would have made a much more responsible statement in their review. To just say the AC90 has "poor resolution" is so wrong that it's absurd. The proper statement should have read something like:
The AC90 is impressively sharp. Incredibly sharp, and in fact sharper than many other cameras we have tested that have much higher price tags. However, those results only come with apertures that are relatively wide open. All sensors are subject to their imaging softening up due to diffraction, but because of the small sensors and how many pixels are crammed onto those sensors, the AC90's diffraction limit happens quite early in the iris range. Any iris deeper than f/2.8 can show softening of the image due to diffraction; the red channel starts to be impacted by about f/2.8. Panasonic has worked around this by creating an integrated ND filter that keeps the iris in the "sweet spot" much longer than you would otherwise expect; because of the way the ND filter works, the physical iris actually stays in the sweet spot up until the iris gauge reads f/6.4. So we can report that you will have crystal clear images and razor sharp resolution at any iris between wide open (f/1.5) and f/6.4. And even then, diffraction will be of minimal impact to the image up to about f/8.0. We don't recommend using irises deeper than f/8.0, but you should get sharp images at f/8, and crystal-clear razor sharp images anywhere from f/6.4 up to f/1.5."

That would have been a responsible, informative, and useful description. Saying it has "poor resolution" is just irresponsible and factually inaccurate.

 

[Rod Pike]

Nice one Barry. Succinct, informative and understandable. (like your books). You should charge them for that piece of copy! This AC90 looks more and more like an addition to my steadicam rig.

 

[Tom Roper]

It seems like I've seen some softening in a few circumstances attributable to using DRS, or having Detail Coring higher than -2. One circumstance was at f/3.8, a high contrast outdoor scene where I was reducing exposure with shutter and external ND to keep the sky from clipping. Then, to assist the shadows details from being crushed, I used DRS 1. The gamma was Cine-D. The focus was manually performed using focus assist. You can sometimes go wrong trying to manual focus a deep dof camera lens, the auto focus seems almost completely reliable. The other shots taken at the same time were razor sharp. I think I've noticed the lens seems like it could be slightly softer at the very widest, and zooming from +10 all the way to full telephoto is very sharp. It's the only recent camera where it occurred to me that full wide wasn't as quite at it's sharpest, but it's very hard for me to say, partly because it's maybe a little bit wider than other lenses, or at least from memory seems wider than the TM900.

It's not worth worrying about, just remember going to -2 or -3 on the Detail Coring really crispens the image in a subtle good way, absent the ugly halos you get from excessive edge enhancement. The details are highly resolved without drawing false outlines around objects. It's that organic characteristic that among others sets this camera apart from consumer cams. The colors are accurate as well, the ATW white balance gets the scene right after a few seconds at worst, lock it and shoot.

And has anyone else commented on the 8 blade iris? Impressive! You don't expect or get shallow depth of field or bokeh, but it's actually quite excellent. For example, shoot a subject from a few inches away and add some zoom. The background (a few feet behind) blurs into complete oblivion and bokeh is excellent. You will be surprised. How useful? For macro it's possible, so there are some creative possibilities.

It's not a perfect camera, but I can't think of one I've used so adroit at getting the most from tiny chips, to make an image that overall is professional, the white balance, color accuracy, organic, and stabilization. You can do many more things at a high level with this versatility.

 

[bluesgeek]

Is it too early to start an AC90 firmware feature request thread?

I want more control over what I can choose to display when the Display Mode button is OFF. For example, I usually want audio meters, and often lens info to always be displayed. I am often taking in a feed from a play-by-play audio mixer and am responsible for keeping that signal healthy. Also because the zoom/focus is electronic I tend to rely more on the lens information for sports/action shooting. But I don't need to see OIS status, WB, IA/MNL mode, Iris mode, or TC (the latter of which is a huge font size).

Also, I want an option for Guides visibility when Focus Assist is activated.

 

[Barry_Green]

The timecode can already be disabled separately; use the COUNTER button for that.

 

[bluesgeek]

Thank you, Barry!

 

[andre]

I would like an autoshutter on/off selection, so I can decide to automatically go for higher shutter speeds or use an external ND filter to fight diffraction.

 

[AlbertoT]

Yes.

Hello Barry,

just out of curiosity, speaking of batteries, would the camera still work with a smaller size battery, like the CGP-D28S/D320 or the CGR-D16S/D220? They are lower capacity but voltage and attachment are the same, so theoretically they should work, instead of getting 4-5 hours of operation you get 2 or 3, but in same cases this may not be an issue. Do you confirm?

On another note, I thought the viewfinder was not that good and it had especially that 'rainbow effect' that one (me) gets with DLP projectors. What's your take on that?

What about the loss of detail during panning?

Any chance of setting the speed of the main zoom rocker or have it with a gradual start/stop?

Finally, do you think the AC90 could pass for some low-profile broadcast use or is too much to ask? I am thinking about the codec and the small sensor, the latter even with an external recorder. Do you think we could get away with it because the image quality is otherwise very good? TVs are very finicky about codecs and sensor sizes, but it's easy for them to lay requirements....

 

[Barry_Green]

I would like an autoshutter on/off selection, so I can decide to automatically go for higher shutter speeds or use an external ND filter to fight diffraction.

It has that. You can tell it whether you want it to automatically control shutter or not. You can have full independent manual shutter control, or allow it to automatically control.

 

[Barry_Green]

Hello Barry,

just out of curiosity, speaking of batteries, would the camera still work with a smaller size battery, like the CGP-D28S/D320 or the CGR-D16S/D220? They are lower capacity but voltage and attachment are the same, so theoretically they should work, instead of getting 4-5 hours of operation you get 2 or 3, but in same cases this may not be an issue. Do you confirm?

I don't have any of those smaller batteries anymore to test, but I can't see why they wouldn't work. Should work, I would think. But that's only a guess, as I can't try it.

 

[FL Jones]

Yes, that would be certainly informative to know.

As Chris has said, yes -- I consider external ND filtration mandatory with this camera when used in bright light conditions, because you cannot/should not/must not go stopping the iris down to f/11 or anywhere close to it.

If they tested an AC90 and found it "soft", that can only be attributed to not understanding the system and using it in error. I repeat, the AC90 is razor sharp, period.

Hello Barry,

Thank you for your detailed and informative posts about the Panasonic AG-AC90.

I’m considering purchasing this camera for mostly outdoor videos around water, like ocean sport fishing, and other ocean related scenes. In your posts you state that using a 2 or 3 stop ND filter is a must to keep the iris in the sweet spot in bright light situations to maximize image clarity. What is your opinion about using a polarizing filter in combination with the ND filter? Did you use one in your Caribbean footage, with or without an ND? Will stacking filters interfere with the image when the lens set to its widest focal length?

Thank you.

 

[Barry_Green]

The main thing about the need for an ND filter is to keep the shutter from going too high also; much of what I shot was at 1/500 and 1/1000, and that's too high a speed to render motion naturally. So it's a combination of keeping the iris open enough (ideally f/6.4 or more open) and also keeping the shutter speed down to a reasonable maximum (like 1/120).

In the Dominican footage I used no filters whatsoever. I wasn't really trying to gather "beauty" footage, I was trying to test the camera itself, without additional products.

A polarizer is always a good thing to have in the kit, but -- polarizers are challenging filters to shoot with. Their effectiveness varies depending on which direction you're pointing the camera and on where the sun is in the sky, and also in how far you've rotated the filter. For a locked-down staged shot a polarizer can make a huge difference in the quality of your footage, but for something where you're pointing the camera in different directions frequently, I'd say avoid a polarizer at all costs, as the effect will "come and go" depending on which way you're pointing the camera in relation to the sun.

I would definitely recommend a good three-stop ND if you're going to be in broad sunlight frequently. And by good, I mean a real, genuine, high-quality, best-brand filter. Not some cheapo thing; you never want to skimp on anything that goes in front of your lens. I recommend B+W, Schneider, and Heliopan as my preferred brands. Get the very best filter you can, and avoid all variable-ND filters as they all degrade the footage to some degree or other, some of them terribly so. Get a great-quality, cinema-quality, white-water glass, pristine ND filter, and it'll let the sharpness of the AC90 footage shine through.

 

[FL Jones]

Barry,

Thank you very much for your prompt reply about the ND and polarizing filters. Great advice. I really appreciate the thought and detail that you provide in your posts.

Frank

 

[Peter Rush]

Barry - I've preordered an AC-90 to replace my ageing Sony Z1 - one of the great features of the Z1 was WB compensation that could be assigned to the user buttons - great for instant warming or cooling - I notice the AC-90 has user assign buttons - does it also have WB compensation?

Pete

 

[bluesgeek]

You can manually make two settings (A and B) the same. You can then finely adjust one of them to be warmer or cooler, which you can then select quickly with the white balance button. But white balance selection is not one of the user button functions.

 

[Benjobe]

If you were shooting F6.4 and shutter 1/1000th without a ND filter, then would a 3-stop ND filter be sufficient to shoot F2.0 shutter 1/50th? Seems to me like a 6-stop ND filter would be better. Of course, it'd be nice to have both as an option.

 

[Barry_Green]

does it also have WB compensation?

As bluesgeek said, you can compensate the white balance, you have 15 steps of control, you can make it go very slightly blue or very slightly orange, or massively blue, or massively orange, or anywhere inbetween in 15 steps. There are two white balance channels and you can configure each separately.

 

[Barry_Green]

If you were shooting F6.4 and shutter 1/1000th without a ND filter, then would a 3-stop ND filter be sufficient to shoot F2.0 shutter 1/50th? Seems to me like a 6-stop ND filter would be better. Of course, it'd be nice to have both as an option.

Six stops would get you there, but is it really necessary? F/6.4 and f/2.8 are identical in terms of aperture on this camera, because of the way the ND filter works, so really all you really really need to do is rein in the shutter speed. Going that extra stop more open wouldn't give you much, as you'd already be in the sweet spot of the lens, and DOF control is minimal on a camera with chips this small such that I don't think the extra stop will make much difference.

If you want six stops you can certainly go for it, and it would give you more options. I consider two stops an absolute minimum that someone should have with them, and I think three might be better; nothing wrong with having a six-stop ND1.8 in your kit if you can afford it, just so long as you get a very high quality ND filter and not some junky ebay special or freebie "digital optics" junk.